Distance-measuring instrument of the coincident-image type.



B. BERNIOK. DISTANCE MEASURING INSTRUMENT OF THE COINCIDENT IMAGE TYPE. APPLICATION FILED NOV. 25. 1911.

1,@38,83L Patented Sept. 17,1912.

UNITED STATES PATENT orrron.

ERNST BERNIQK, 0F BIGA, RUSSIA, ASSIGNOR '.[0 THE FIRM 0F OPTISCHE ANS'IALT C. P. GOERZ AKTIENGESELLSCHAFT, OF FRIEDENAU, NEAR BERLIN, GERMANYu DISTANCE-MEASURINGINSTRUMENT OF THE COINCIDENT-IMAGE TYPE. I

Specification of Letters I'atent.

To all who-n5. it may concern:

Be it known that I, En vs'r BEBNICK, citizen of the German Empire, residing at Niko-laistrasse, Riga, Russia, have invente certain new an useful Improvements in Distance-Measuring Instruments of the Coincident-Image Type, of which the following is a specification.

This invention relates to distance measuring instruments of the coincident image type, that, is to say, distance measuring nstruments wherein images of a distant object appear at opposite sides of a dividing line and are brought into coincident relation with each: other at corresponding points by means of adjusting mechanism.

The object of the invention is to provide, in distance measuring instruments of this class, in which images inverted or symmetricalrelatively to each other appear at opposite sides of the dividing line of the field, means whereby the upright and the inverted image can be displaced relatively to the dividing line so that any desired points of the objects lying above and below, or to the right and left, can be brought into coincidence. his enables account to be taken of the various shapes of the objects observed, the most striking features thereof being utilized r'or the purpose of the adjustment.

The invention is illustrated in the accompanying drawing, in which Figures 1 and 2 are diagrammatic views of image fields of distance measuring instruments constructed according to the invention. Fig. 3 shows one form of ocular prism arrangement of a distance measuring instrument constructed according to the invention. Fig. 4 shows a prism device with reflecting layers corresponding to the form of the field of view illustrated in Fig. I. Fig. 5 illustrates in perspective view the arrangement of reflecting layers in the prism device of Fig. 4 corresponding to the field of view illustrated in Fig. 2. Fig. 6 shows the field of view which results from an ar'- rangement of the reflecting layers in the ocular prism device of the instrument illustrated in Fig. 3., a

In the view shown in Fig. 1 ofthe image field of a distance measuring instrument the dividing line of the field is marked a. This dividing line. traverses-the entire diameter of the field. At opposite sides of the dividing line he field sections b,. b which which, like the obj ectivesl m an are hatched in the drawing, and each of which contacts with only part of the dividing line. a, and 0, are two other sections of the field, which," like the sections 12, b,. only contact with parts ofthe dividing line. The objects which appear in the sections 7), I), appear upright, as illustrated, for example, in the case of an air-ship d (i the air-ship in the section b beingshown in solid lines and that in the section b in dotted lines. In the sections 0, a, the images of the object appear The observation of the object 11 d may be made in the sections b, 0 in which case the bottom portions are brought into coincidence at the dividing line a, or in the sections 6,. 0

in which case the top portions are brought into coincidence. By turning the instrument through a small angle the object can be shifted from b, 0 to 12 0,, or vice versa.

In the imagefield in Fig. 2 there is also a dividing line a, at opposite sides of which are field sections 6 0, and 15 0,. are ,also marked '(Z (1 In the arrangement of ocular prisms shown in Fig.3, giving an image field of inverted, as shown in section 0, in. solid lines and in sect1on a, 1n dotted lines.

Patented Sept. 1'7 1912. Application filed November 25, 1911. Serial No. 662,283.

The objects the kind shown in Fig. 6, a reflective coating is rovided at the contact surface of a three-sided rectangular prism c and a rhombohedral prism f, this coating consisting of two parts, the border line of which is arts of said marked g. One of the two lies above coating, namely, the section the-line g, and the second section h, belowsame. On the back side of the composite,

prism e f, that is to say in the path of the the distant object and rays coming from entering the composite prism, there are two" prism bodies 71 k, which project to the prism body 0 f, the rays coming from the ob ectives l m of the distance measuring instru- .ment. The observation of ,the image field The rays-5 directed toward 9 is made through the ocular n."- from the distant object are the objectives 1 m by pentagonal fI'lSmS-Qji,

the-ocular n, are only diagrammatically indicated in the drawing by dotted lines. g' marks the position line of the distance measuring-1m str umentl The border line .9 of themirror surfaces h h, is parallel with the position line 9 and lies in the field of the objectives -l m and ocular n. Ifthat part of the prjsm body 6 f is used. which in the drav'iuflfl. i

I tliat on the other side reversed, the prism la,

.. t g into theflocular a,

has a. roof edge, the prism 2' being merely a three side rectangular prism without roof ;edge. l-Vhenthe left hand partof the prism body. ,6 f is used for observation the rays from the objective Z with the exception of those intercepted by theback of the reflective coating /5 pass without reflection through the prism body 6 fabove the line whereasthe rays from the objective in, after being reflected by a surface of the rhombohedral prism f and the surface b below the border line g, enter the ocular il vhenthe right hand half of the prism body e f is used for observation the rays from the objective Z pass below the blirder line gin the image field without reflection directly through the prism body et, whereas the rays from m pass out over the line g, after reflection by a surface of the rhombohedral prism and by the mirror and enter the ocular n. Thus the images shown in Fig. 6 are produced in "the field, according to whether the right Ilia-nil or left hand half is used. The translation from one image position to the other is made simplybyrotating the instrument about its vertical axis, without requiring correction ofthe image position by adjustment f optical elements of the instrument. After the rotation, of course, the images are brought into coincidence at the most favorable point, by slight tilting. y

In the case of distance measuring inst-ruments which aremainly used for observation'off objects on the ground, whereof the most strilgingfeatures areusually at the top it .is desirable toihave the field section used for such observations larger than that which is used for observation of objects whereof theis usually at t-he botmost striking feature tom, for example air-ships.

device provided with X convenient divison of the field is shown in Fig. 2.

The arrangement of reflecting surfaces 71,, it, in the contact surface of prisms e, f which results in the formation of the'field of view illustrated in Fig. 2 is represented in 5. Fig. 4 shows the arrangement of the reflecting coatings in the contact surface between prisms e and f resulting, in the formation of a field of view in Fig. 1.

, Instead of having the dividing line-horizontal in the field it may be substantially vertical, as is usual in the case of so-callcd symmetry distance measuring instruments, the latter being, in this specification, included in the general term coincident image instruments. iv

What- I claim is I 1., In a base line telemeter qne ocular and image producing and reflecting means adapted to produce two images ofdistant objects in juxtaposition with each other in the fieldof view of the ocular, the reflecting means comprising reflecting surfaces forming a substantially straight edge traversing the field of view, said reflecting surfaces arranged partially on the one and partially on the other side of said straight edge.

2. In a base line telemeter an ocular prism reflecting surfaces havmg a limiting edge in an image plane of the instrument forming the dividing line in the image field-the reflecting surfaces producing the dividing line lying partly on one and partly on the other side of'said limiting edge in the image plane.

In a base line telemeter an ocular prism device comprising two prisms contacting with each other in a surface crossing the image field, reflecting layers provided in said contact surface having a limiting edge parallel to the base line of the instrument and coincident with an image plane of the instrument said reflecting layers having sections positioned on opposite sides of said limiting edge.

.In testimony whereof I have signed .this specification in the presence of two subscribing Witnesses.-

ERN ST 'BERNICK.

l/Vitnesses HENRY HAsrnn, VVoLonMAn IIAUPT. 

